In the field of ultraviolet curing systems, the ultraviolet lamps generate large quantities of heat. This generated heat is a by-product of and is unwanted in the manufacture of business forms. A high intensity curing system provides for rapid drying of the ink. However, the high intensity system uses a large amount of power and also shortens lamp life due to high temperature. Additionally, the high intensity system causes overheating of the paper or other record media which carries the printing ink.
A number of ways for controlling the heat in ultraviolet curing systems have been recommended. A popular method of controlling the heat is by providing cooling in the system. The cooling of ultraviolet curing systems has been accomplished by high volume purging of the air in the vicinity of the ultraviolet lamps, by use of infrared filters between the lamps and the record media, by the use of heat sinks along the path of the record media, and by use of water-cooled lamp reflectors.
It is important to provide a curing system that deals with high production output while realizing maximum efficiency of the costs of operation.
Representative documentation in the area of ultraviolet lamp control includes U.S. Pat. No. 3,984,726, issued to W. J. Ramler on October 5, 1976, which discloses ultraviolet light processors containing a plurality of ultraviolet light sources wherein the processors are improved by providing means for increasing the intensity of one lamp to compensate for a reduction in intensity of another lamp so that the total intensity of the system is substantially the same.
U.S. Pat. No. 4,005,135, issued to N. A. Helding on Jan. 25, 1977, discloses an ultraviolet curing lamp system having rotatable reflector assemblies and wherein the lamp power is reduced at the time the reflector assemblies are rotated.
U.S. Pat. No. 4,220,865, issued to S. Silverman on Sept. 2, 1980, discloses an ultraviolet curing oven wherein air flow paths are provided to cool the lamps and reflectors during high power operation and to enable the lamp to stay hot during low power operation.
U.S. Pat. No. 4,495,713, issued to M. Williner on Jan. 29, 1985, discloses infrared radiation devices wherein energy is saved during drying of film if the power is automatically varied in accordance with temperature measurements taken on circulating air.
And, U.S. Pat. No. 4,665,627, issued to H. J. Wilde on May 19, 1987, discloses ultraviolet lamps which are controlled by a circuit that regulates the intensity of the lamps to a set level as the lamps age. A sensor provides a signal that is directly proportional to ultraviolet light intensity and this signal is used to adjust the power to the lamps through a microprocessor controlled power source to maintain the UV intensity at the set level.